It could be because of that (not sure yet) , but also because of the size of the image that you actually uploaded.

Go to this link in your User CP and it will tell you the maximum size it can be. When you do that, will you copy and past what it says here, please? I want to see if it's different for regular members (you) and premium members (me).

Mine, as a premium member, says: "Note: The maximum size of your custom image is 600 by 420 pixels or 395.3 KB (whichever is smaller)." Is your's different?

ETA: Are you talking about your profile picture or your avatar... because now I see they are the same. I'm confused

Oh no my bad! (SORRY!) ...I thought my profile pic wasn't showing but it was the avatar pic..which I have now uploaded and I can see it now when I post (I thought that was where the profile pic was shown)..so all good - problem solved